| 1. |
- Augustsson, Per, et al.
(författare)
-
Automated and temperature-controlled micro-PIV measurements enabling long-term-stable microchannel acoustophoresis characterization.
- 2011
-
Ingår i: Lab on a Chip. - : Royal Society of Chemistry (RSC). - 1473-0189 .- 1473-0197. ; 11:24, s. 4152-4164
-
Tidskriftsartikel (refereegranskat)abstract
- We present a platform for micro particle image velocimetry (μPIV), capable of carrying out full-channel, temperature-controlled, long-term-stable, and automated μPIV-measurement of microchannel acoustophoresis with uncertainties below 5% and a spatial resolution in the order of 20 μm. A method to determine optimal μPIV-settings for obtaining high-quality results of the spatially inhomogeneous acoustophoretic velocity fields of large dynamical range is presented. In particular we study the dependence of the results on the μPIV interrogation window size and the number of repeated experiments. The μPIV-method was further verified by comparing it with our previously published particle tracking method. Using the μPIV platform we present a series of high-resolution measurements of the acoustophoretic velocity field as a function of the driving frequency, the driving voltage, and the resonator temperature. Finally, we establish a direct and consistent connection between the obtained acoustophoretic velocity fields, and continuous flow mode acoustophoresis, commonly used in applications.
|
|
| 2. |
- Barnkob, Rune, et al.
(författare)
-
Acoustic radiation- and streaming-induced microparticle velocities determined by microparticle image velocimetry in an ultrasound symmetry plane
- 2012
-
Ingår i: Physical Review E (Statistical, Nonlinear, and Soft Matter Physics). - 1539-3755. ; 86:5
-
Tidskriftsartikel (refereegranskat)abstract
- We present microparticle image velocimetry measurements of suspended microparticles of diameters from 0.6 to 10 mu m undergoing acoustophoresis in an ultrasound symmetry plane in a microchannel. The motion of the smallest particles is dominated by the Stokes drag from the induced acoustic streaming flow, while the motion of the largest particles is dominated by the acoustic radiation force. For all particle sizes we predict theoretically how much of the particle velocity is due to radiation and streaming, respectively. These predictions include corrections for particle-wall interactions and ultrasonic thermoviscous effects and match our measurements within the experimental uncertainty. Finally, we predict theoretically and confirm experimentally that the ratio between the acoustic radiation-and streaming-induced particle velocities is proportional to the actuation frequency, the acoustic contrast factor, and the square of the particle size, while it is inversely proportional to the kinematic viscosity.
|
|
| 3. |
- Barnkob, Rune, et al.
(författare)
-
Measuring acoustic energy density in microchannel acoustophoresis using a simple and rapid light-intensity method
- 2012
-
Ingår i: Lab on a Chip. - : Royal Society of Chemistry (RSC). - 1473-0197 .- 1473-0189. ; 12:13, s. 2337-2344
-
Tidskriftsartikel (refereegranskat)abstract
- We present a simple and rapid method for measuring the acoustic energy density in microchannel acoustophoresis based on light-intensity measurements of a suspension of particles. The method relies on the assumption that each particle in the suspension undergoes single-particle acoustophoresis. It is validated by the single-particle tracking method, and we show by proper re-scaling that the re-scaled light intensity plotted versus re-scaled time falls on a universal curve. The method allows for analysis of moderate-resolution images in the concentration range encountered in typical experiments, and it is an attractive alternative to particle tracking and particle image velocimetry for quantifying acoustophoretic performance in microchannels.
|
|
| 4. |
- Barnkob, Rune, et al.
(författare)
-
Measuring density and compressibility of white blood cells and prostate cancer cells by microchannel acoustophoresis
- 2011
-
Ingår i: 15th International Conference on Miniaturized Systems for Chemistry and Life Sciences 2011, MicroTAS 2011. - 9781618395955 ; 1, s. 127-129
-
Konferensbidrag (refereegranskat)abstract
- We present a novel method for the determination of density and compressibility of individual particles and cells undergoing microchannel acoustophoresis in an arbitrary 2D acoustic field. Our method is a critical advancement within acoustophoretic separation of biological cells, as the ability to determine the density and compressibility of individual cells enables the prediction and alteration of the separation outcome for a given cell mixture. We apply the method on white blood cells (WBCs) and DU145 prostate cancer cells (DUCs) aiming to improve isolation of circulating tumor cells from blood, an emerging tool in the monitoring and characterizing of metastatic cancer.
|
|
| 5. |
- Barnkob, Rune, et al.
(författare)
-
Measuring the local pressure amplitude in microchannel acoustophoresis
- 2010
-
Ingår i: Lab on a Chip. - : Royal Society of Chemistry (RSC). - 1473-0189 .- 1473-0197. ; 10:5, s. 563-570
-
Tidskriftsartikel (refereegranskat)abstract
- A new method is reported on how to measure the local pressure amplitude and the Q factor of ultrasound resonances in microfluidic chips designed for acoustophoresis of particle suspensions. The method relies on tracking individual polystyrene tracer microbeads in straight water-filled silicon/glass microchannels. The system is actuated by a PZT piezo transducer attached beneath the chip and driven by an applied ac voltage near its eigenfrequency of 2 MHz. For a given frequency a number of particle tracks are recorded by a CCD camera and fitted to a theoretical expression for the acoustophoretic motion of the microbeads. From the curve fits we obtain the acoustic energy density, and hence the pressure amplitude as well as the acoustophoretic force. By plotting the obtained energy densities as a function of applied frequency, we obtain Lorentzian line shapes, from which the resonance frequency and the Q factor for each resonance peak are derived. Typical measurements yield acoustic energy densities of the order of 10 J/m(3), pressure amplitudes of 0.2 MPa, and Q factors around 500. The observed half wavelength of the transverse acoustic pressure wave is equal within 2% to the measured width w = 377 mu m of the channel.
|
|
| 6. |
- Soller, Richard, et al.
(författare)
-
Single-cell mass-density measurements using microchannel gradient centrifugation
- 2022
-
Ingår i: MicroTAS 2022 - 26th International Conference on Miniaturized Systems for Chemistry and Life Sciences. - 9781733419048 ; , s. 717-718
-
Konferensbidrag (refereegranskat)abstract
- We present a microchannel-based adaption of density-gradient centrifugation that allows the instantaneous, precise, and repeatable generation of a 1-dimensional mass-density gradient and determination of single-cell densities with integrated mass-density calibration.
|
|
